Quantitative expression of defense-related genes induced in Theobroma cacao by Bion and Agro-Mos inducers against Crinipellis perniciosa / ExpressÃo quantitativa de genes relacionados à defesa induzida em Theobroma cacao por Bion e Agro-Mos contra Crinipellis perniciosa.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Cocoa witcheâs broom disease caused by the fungus Crinipellis perniciosa is considered the main disease on cocoa (Theobroma cacao), which damages led Brazil from an exporter to an importer country of cocoa beans. The induction of defense-related genes represents the best molecular markers to study elicitor- mediated defense activation. The objective of this research was to analyze the quantitative gene expression of defense-related genes (peroxidase and chitinase) induced by Bion and Agro-Mos in inoculated or uninoculated cocoa plants, by using RT-qPCR. POD- and CHI-like genes were induced in cocoa plants by both resistance inducers, but leading to quite distinct expression profiles. It was observed two expression peaks for both genes, indicating the detection of the de novo synthesis. Gene expression induced by Bion occurred more rapidly than that induced by Agro-MosÂ. In addition, a potentiation in expression of the genes was observed to be caused by the pathogen infection, showing putative priming effect, which revealed to be different between inducers, genes, as well as the expression profile during the analyzed period. Non-induced susceptible genotype âcv Catongoâ responded to the pathogen with enhanced levels of POD e CHI gene expression; however levels of POD were kept high while CHI levels were suppressed by the pathogen. The potential of the Agro-Mos to stimulate the expression of defense genes, probably occurred in an inespecific cascade not yet well characterized, which may be different to the BionÂ-induced cascade.

ASSUNTO(S)

fitossanidade

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